Stator for a high efficiency motor and manufacturing methods thereof

ABSTRACT

A stator for a high efficiency motor and a manufacturing method of a stator for a high efficiency motor are disclosed. The method includes: preparing filling powder by coating a surface of soft magnetic powder with an insulating layer; providing a stator core partitioned into a center hole and inner spaces, the stator core including a yoke portion and a plurality of teeth; coiling coils around the plurality of teeth located in the inner spaces, respectively; and filling the inner spaces with a mixture of the filling powder and an adhesive, and curing the mixture of the filling powder and the adhesive.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority to Korean Patent Application No.10-2016-0137800, filed Oct. 21, 2016, the entire content of which isincorporated herein for all purposes by this reference.

BACKGROUND 1. Field

The present disclosure relates generally to a stator for a motor and amanufacturing method thereof. More particularly, the present disclosurerelates to a manufacturing method of a stator for a high efficiencymotor whereby the stator is capable of improving performance of themotor by minimizing magnetic flux leakage and iron loss generatedbetween teeth of the stator with coils coiled around the teeth.

2. Description of the Related Art

A motor converting electric energy into a rotational force as a powersource for driving a vehicle may be provided in an eco-friendly vehicle,such as an electric vehicle, a hybrid electric vehicle, or a fuel cellvehicle.

The motor includes a stator and a rotor. The stator is installed insidea housing of the motor, and the rotor is disposed inside the stator.

FIG. 1 is a view illustrating an integrated stator according to therelated art, and FIG. 2 is a view illustrating a stator provided byusing split cores according to the related art.

As shown in FIGS. 1 and 2, in a stator of a motor according to therelated art, the stator including a yoke portion 110 and a plurality ofteeth 112 is integrally provided such that a center hole 101 and innerspaces 102 are formed in the stator. Alternatively, the stator isprovided in such a way that a plurality of split cores 100 a is disposedin a ring shape. In this regard, the split cores 100 a include: backyokes 111 formed along outer circumference of the stator; and teeth 112protruding from the back yokes 111 toward the center of the stator ofthe motor. Further, coils 200 made of copper are coiled around the teeth112.

FIG. 3 is a view illustrating the stator of the motor with the coilscoiled around teeth of the stator according to the related art. FIGS. 4Aand 4B are views illustrating magnetic flux density and iron loss of thestator of the motor according to the related art, respectively.

As shown in FIG. 3, and FIGS. 4A and 4B, in the stator of the motoraccording to the related art, parts of the teeth 112 with coils coiledaround the parts illustrate high magnetic flux density and high ironloss, and spaces between the teeth with the coil coiled around the teethillustrate high iron loss due to magnetic flux leakage.

Due to high magnetic flux leakage and the high iron loss describedabove, performance of an AC motor deteriorates. Thus, technicaldevelopment is urgently required to minimize magnetic flux leakage andiron loss.

The foregoing is intended merely to aid in the understanding of thebackground, and is not intended to mean that the present disclosurefalls within the purview of the related art that is already known tothose skilled in the art.

SUMMARY AND DESCRIPTION

Accordingly, the present disclosure has been made keeping in mind theabove problems occurring in the related art, and the present disclosureis intended to propose a manufacturing method of a stator for a highefficiency motor whereby the stator is capable of improving performanceof the motor by minimizing spaces between teeth of the stator with coilscoiled around the teeth and by preventing magnetic flux leakage and ironloss from occurring.

In order to achieve the above object, according to one aspect, amanufacturing method of a stator for a high efficiency motor isprovided. The method includes: preparing filling powder by coating asurface of soft magnetic powder with an insulating layer; providing astator core partitioned into a center hole and inner spaces, the statorcore including a yoke portion and a plurality of teeth; coiling coilsaround the plurality of teeth located in the inner spaces, respectively;and filling the inner spaces with a mixture of the filling powder and anadhesive, and curing the mixture of the filling powder and the adhesive.

The preparing of the filling powder may include: mixing the softmagnetic powder, insulation powder, and a reaction accelerator togetherto prepare a first mixture powder; milling the first mixture powder sothat the insulation powder adheres to the surface of the soft magneticpowder to prepare a second mixture powder; and heat-treating the secondmixture powder so that the insulating layer is formed on the surface ofthe soft magnetic powder to prepare the filling powder.

In the mixing of the soft magnetic powder, the insulation powder, andthe reaction accelerator, the insulation powder may be alumina powderand the reaction accelerator may be ammonium chloride powder.

In the mixing of the soft magnetic powder, the insulation powder, andthe reaction accelerator, the first mixture powder may be prepared bymixing the soft magnetic powder, the alumina powder, and the ammoniumchloride powder at a mass ratio of 60-90:9-39:1, respectively.

In the heat-treating of the second mixture powder, the second mixturepowder may be heat-treated at a temperature of 750-1300° C. for 10-24hours, for example, to form the insulating layer on the surface of thesoft magnetic powder.

The method may further include forming core covers by applying themixture to upper and lower surfaces of the stator core filled with themixture, and by curing the mixture after the filling of the innerspaces.

In the providing of the stator core, the stator core may be provided insuch a way that a plurality of split cores having respective back yokesand teeth is radially disposed to form the center hole and the innerspaces.

A stator for a high efficiency motor, the stator includes: a stator corepartitioned into a center hole and inner spaces, the stator coreincluding a yoke portion and a plurality of teeth; coils coiled aroundthe plurality of teeth, respectively; and filling parts filling theinner spaces, respectively, to prevent magnetic flux leakage fromoccurring between the coils coiled around the plurality of teeth.

The stator core may be provided in such a way that a plurality of splitcores having respective back yokes and teeth is radially disposed toform the center hole and the inner spaces.

The plurality of split cores having the respective back yokes and theteeth may be radially disposed, each of the back yokes being providedwith a coupling protrusion formed on a first side thereof, and with acoupling groove formed on a second side thereof.

The stator may further include a pair of core covers coupled to upperand lower surfaces of the stator core, respectively.

The filling parts and the core covers may be made of filling powderprovided by coating a surface of soft magnetic powder with an insulatinglayer made of alumina.

The present embodiments are advantageous as follows. The presentembodiments can minimize magnetic flux leakage and iron loss by fillingspaces between a plurality of radially disposed teeth having coilscoiled around the teeth with a soft magnetic mixture. Thus, the presentembodiments can improve efficiency of a motor.

Furthermore, the present embodiments can improve efficiency and torqueof a motor and can reduce size and weight of the motor by preventingmagnetic flux leakage and iron loss generated from upper and lowersurfaces of a stator of the motor and by gathering magnetic flux. Thus,the present embodiments can reduce weight of a vehicle and improve fuelefficiency.

Furthermore, the present embodiments can improve performance of a statorfor a high efficiency motor and can reduce a size of the stator bypreventing magnetic flux leakage and by gathering magnetic flux. Thus, alight weight vehicle can be realized by the stator.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages are moreclearly understood from the following detailed description when taken inconjunction with the accompanying drawings, in which:

FIG. 1 is a view illustrating an integrated stator according to therelated art;

FIG. 2 is a view illustrating a stator provided by using split coresaccording to the related art;

FIG. 3 is a view illustrating a stator of a motor with coils coiledaround teeth of the stator according to the related art;

FIGS. 4A and 4B are views illustrating magnetic flux density and ironloss of the stator of the motor according to the related art,respectively;

FIG. 5 is a diagram illustrating a manufacturing method of a stator fora high efficiency motor according to an embodiment;

FIG. 6 is a view illustrating filling powder according to an embodiment;

FIG. 7 is a plan view illustrating the stator for the high efficiencymotor according to an embodiment;

FIG. 8 is a side view illustrating the stator for the high efficiencymotor according to an embodiment; and

FIG. 9 is a view illustrating magnetic flux density and iron loss of thestator for the high efficiency motor according to an embodiment.

DETAILED DESCRIPTION

Hereinbelow, exemplary embodiments are described in detail withreference to the accompanying drawings. Throughout the drawings, thesame reference numerals will refer to the same or like parts.

FIG. 5 is a diagram illustrating a manufacturing method of a stator fora high efficiency motor according to an embodiment.

As shown in FIG. 5, the method according to an embodiment includes:preparing filling powder 10; providing a stator core 100 partitionedinto a center hole 101 and inner spaces 102, the stator core 100including a yoke portion 110 and a plurality of teeth 112; coiling coils200 around the teeth 112 of split cores 100 a, respectively; and fillingthe inner spaces 102 with a mixture of the filling powder 10 and anadhesive.

The preparing of the filling powder 10 provided by coating a surface ofsoft magnetic powder 11 with an insulating layer 12 includes: mixing,milling, and heat-treating processes.

In the mixing process, a first mixture powder is prepared by mixing thesoft magnetic powder 11, insulation powder, and a reaction acceleratortogether.

A soft magnetic material having high magnetic flux density may beutilized as the soft magnetic powder 11. The soft magnetic material maybe: Fe, Fe—Si, Fe—Co, Fe—Ni, Fe—Al, Fe—Si—Al, Ni—Fe—Mo, Fe—Si—Cr,Fe—Si—Cr—Al, Fe—Si—B, Fe—Si—B—Cu—Nb, Mn—Zn ferrite, or Ni—Zn ferrite.

Furthermore, the insulation powder prevents the coils 200 respectivelycoiled around the teeth 112 and located in the inner spaces 102 of thestator core 100 from applying an electric current to each other. Aluminapowder Al₂O₃ may be utilized as the insulation powder.

In this case, the insulation powder is not limited to the aluminapowder. Further, an inorganic oxide, such as silicon oxide, or variousmaterials, such as phosphate, resin, and glass materials, may beselectively utilized as the insulation powder as long as the materialshave insulating properties to prevent the neighboring coils 200 fromapplying an electric current to each other.

The reaction accelerator made of ammonium chloride NH₄Cl is utilized toimprove reactivity of the insulation powder made of alumina.

In the mixing process, the soft magnetic powder 11, the insulationpowder, and the reaction accelerator may be mixed with each other at amass ratio of 60-90:9-39:1, respectively, to prepare the first mixturepowder.

In this case, when the mass ratio departs from the above ranges, theinsulating layer 12 is insufficiently formed, and magnetic flux leakageis increased. Further, due to lack of soft magnetism, magneticperformance is decreased. Thus, it is desirable that the mass ratio isdetermined within the above ranges.

When the first mixture powder is prepared, in the milling process, theinsulation powder adheres to the surface of the soft magnetic powder 11by milling the first mixture powder with a ball mill for 10-24 hours,for example, to prepare second mixture powder.

In this case, when the first mixture powder is milled for less than 10hours, the soft magnetic powder 11 and the insulation powder are notuniformly mixed with each other, and the insulation powder does notsufficiently adhere to the surface of the soft magnetic powder 11.Further, when the first mixture powder is milled for more than 24 hours,production costs are increased. Thus, it is desirable that the millingtime is determined within the above time range.

FIG. 6 is a view illustrating the filling powder according to anembodiment.

As shown in FIG. 6, when the second mixture powder is prepared, theinsulation powder adhering to the surface of the soft magnetic powder 11is spread by heat-treating the second mixture powder at a temperature of750-1300° C. for 10-24 hours, for example, so that the insulating layeris formed on the surface of the soft magnetic powder 11 to prepare thefilling powder 10.

In this case, when the second mixture powder is heat-treated at atemperature of less than 750° C. or for less than 10 hours, theinsulation powder made of alumina is not sufficiently spread, and theinsulating layer 12 is not sufficiently formed. Further, when the secondmixture powder is heat-treated at a temperature of more than 1300° C. orfor more than 24 hours, manufacturing costs are increased. Thus, it isdesirable that a temperature and time of the heat-treating process aredetermined within the above ranges.

When the filling powder 10 is prepared, in the providing of the statorcore 100, the stator core 100 including the yoke portion 110 and theplurality of teeth 112 is integrally manufactured such that the statorcore 100 is partitioned into the center hole 101 and the inner spaces102. Alternatively, after the split cores 100 a having respective backyokes 111 and teeth 112 are manufactured, the split cores 100 a areradially disposed, and the back yokes 111 of the split cores 100 a arecoupled to each other to form the yoke portion 110. Thus, the statorcore 100 including the center hole 101 and the inner spaces 102 isprovided.

As described, when the stator core 100 is provided, in the coiling ofthe coils, the coils 200 are coiled around the teeth 112 of the splitcores 100 a located in the inner spaces 102, respectively.

As described, when the stator core 100 with the coils 200 coiled aroundthe teeth 112 is provided, in the filling of the inner spaces, thestator for the high efficiency motor is manufactured by filling theinner spaces 102 of the stator core 100 with the mixture of the fillingpowder 10 prepared in the preparing of the filling powder 10 and theadhesive, and by curing the mixture of the filling powder 10 and theadhesive.

In this regard, in the filling powder 10 filling the inner spaces 102,the soft magnetic powder 11 prevents magnetic flux leakage fromoccurring, and the insulating layer 12 applied on the surface of thesoft magnetic powder 11 prevents the coils 200 disposed adjacently toeach other in the inner spaces 102 from applying an electric current toeach other.

That is, performance of the stator for the high efficiency motor may beimproved in such a way that the filling powder 10 prevents magnetic fluxleakage from occurring and gathers magnetic flux.

The method may further include forming core covers 400 by applying themixture to upper and lower surfaces of the stator core 100 filled withthe mixture, and by curing the mixture after the filling of the innerspaces.

In this case, magnetic flux leakage from the open upper and lowersurfaces of the stator core 100 may be prevented, and magnetic flux maybe gathered by being guided by the core covers 400. Thus, performance ofthe stator for the high efficiency motor may be improved, and a size ofthe stator for the high efficiency motor may be reduced.

Hereinbelow, the stator for the high efficiency motor according to anembodiment is described in detail with reference to the accompanyingdrawings.

FIG. 7 is a plan view illustrating the stator for the high efficiencymotor according to an embodiment, and FIG. 8 is a side view illustratingthe stator for the high efficiency motor according to an embodiment.

As shown in FIGS. 7 and 8, the stator for the high efficiency motoraccording to an embodiment includes: the stator core 100; the coils 200;and filling parts 300.

The stator core 100 is provided in such a way that the stator core 100including the yoke portion 110 and the plurality of teeth 112 isintegrally manufactured such that the center hole 101 and the innerspaces 102 are formed in the stator core 100. Alternatively, the statorcore 100 is provided in such a way that the plurality of split cores 100a having respective back yokes 111 and teeth 112 is radially disposed.

In this regard, in each of the split cores 100 a according to anembodiment, a coupling protrusion 111 a may be formed on a first side ofthe back yoke 111, and a coupling groove 111 b corresponding to thecoupling protrusion 111 a may be formed on a second side of the backyoke 111.

In this case, the plurality of split cores 100 a is radially disposed,and the coupling protrusions 111 a are inserted into the neighboringcoupling grooves 111 b so that the stator core 100 is provided. Thus, itis advantageous in that the stator core 100 may be easily assembled.

The stator for the high efficiency motor may further include: the pairof core covers 400 coupled to the upper and lower surfaces of the statorcore 100, respectively. Further, the filling parts 300 and the corecovers 400 according to an embodiment may be made of the filling powder10 provided by coating the surface of the soft magnetic powder 11 withthe insulating layer 12.

FIG. 9 is a view illustrating magnetic flux density and iron loss of thestator for the high efficiency motor according to an embodiment.

As shown in FIG. 9, in the stator for the high efficiency motoraccording to an embodiment, the filling parts 300 are formed by fillingspaces between coils coiled around the teeth 112 with the filling powder10. Thus, compared to the related art, iron loss is reduced in such away that magnetic flux is gathered and magnetic flux leakage isprevented from occurring by the filling parts 300.

As described, according to an embodiment, it is advantageous in thatiron loss of the stator for the high efficiency motor may be minimizedand performance of the stator for the high efficiency motor may beimproved in such a way that magnetic flux is gathered and magnetic fluxleakage is prevented from occurring. Furthermore, it is advantageous inthat a size of a motor may be reduced by using the stator according toan embodiment.

Although embodiments have been described for illustrative purposes,those skilled in the art will appreciate that various modifications,additions, and substitutions are possible, without departing from thescope and spirit of the disclosure as disclosed in the accompanyingclaims. It is therefore intended that the foregoing description beregarded as illustrative rather than limiting, and that it be understoodthat all equivalents and/or combinations of embodiments are intended tobe included in this description.

It is to be understood that the elements and features recited in theappended claims may be combined in different ways to produce new claimsthat likewise fall within the scope of the present disclosure. Thus,whereas the dependent claims appended below depend from only a singleindependent or dependent claim, it is to be understood that thesedependent claims may, alternatively, be made to depend in thealternative from any preceding or following claim, whether independentor dependent, and that such new combinations are to be understood asforming a part of the present specification.

What is claimed is:
 1. A manufacturing method of a stator for a highefficiency motor, the method comprising: preparing a filling powder bycoating a surface of a soft magnetic powder with an insulating layer;providing a stator core partitioned into a center hole and inner spaces,the stator core including a yoke portion and a plurality of teeth;coiling coils around the plurality of teeth located in the inner spaces,respectively; filling the inner spaces with a mixture of the fillingpowder and an adhesive; and curing the mixture of the filling powder andthe adhesive, wherein the preparing of the filling powder includesmixing the soft magnetic powder, an insulation powder, and a reactionaccelerator together, therein providing a first mixture powder, millingthe first mixture powder so that the insulation powder adheres to thesurface of the soft magnetic powder, therein providing a second mixturepowder, and heat-treating the second mixture powder so that theinsulating layer is formed on the surface of the soft magnetic powder,therein providing the filling powder.
 2. The method of claim 1, whereinthe insulation powder is alumina powder, and wherein the reactionaccelerator is ammonium chloride powder.
 3. The method of claim 2,wherein the first mixture powder is prepared by mixing the soft magneticpowder, the alumina powder, and the ammonium chloride powder at a massratio of 60-90:9-39:1, respectively.
 4. The method of claim 3, whereinthe second mixture powder is heat-treated at a temperature of 750-1300°C. for 10-24 hours.
 5. The method of claim 4, further comprising:forming core covers by applying the mixture to upper and lower surfacesof the stator core filled with the mixture, and by curing the mixtureafter the filling of the inner spaces.
 6. The method of claim 2, whereinthe second mixture powder is heat-treated at a temperature of 750-1300°C. for 10-24 hours.
 7. The method of claim 1, wherein the second mixturepowder is heat-treated at a temperature of 750-1300° C. for 10-24 hours.8. The method of claim 1, further comprising: forming core covers byapplying the mixture to upper and lower surfaces of the stator corefilled with the mixture, and by curing the mixture after the filling ofthe inner spaces.
 9. The method of claim 1, the stator core is providedin such a way that a plurality of split cores having respective backyokes and teeth is radially disposed to form the center hole and theinner spaces.